Research paperArchitecture of the distal and outer domains of the Mid-Norwegian rifted margin: Insights from the RÃ¥n-Gjallar ridges system

- Study of the outer domain of the Mid-Norwegian Vøring rifted margin.
- Detailed interpretation of the Gjallar-RÃ¥n ridges.
- Breakup is a complex and composite (tectono-magmatic) geological process.
- We should discuss 'magma-rich' and 'magma-poor' breakup, and not 'magma-rich' and 'magma-poor' margins.

Based on a 3D seismic cube and regional 2D long-offset seismic reflection profiles, we propose a reconsideration of the architecture of the Mid-Norwegian outer Vøring margin. A system comprising large-magnitude detachment faults and steeper fault arrays was mapped together with key sedimentary markers to provide constraints on the structural history of the outer Rån-Gjallar ridges system. Additionally, a detailed mapping of the so-called 'T-reflection' permitted a revision of the nature, origin and tectono-magmatic significance of this debated major reflector.Based on our results, we develop a more general discussion on the final evolutionary stages of rifted margins, including the construction of the outer domain, the birth of an oceanic spreading centre and the definition of breakup.